A rather large number of alarm systems are presently manufactured to provide protection against various problem situations which may be experienced in a residence, an office or shop building, or any other premises. Fire, burglary, panic, or any other unique situation can be sensed locally and the information then transmitted by a local communicator through appropriate connection to the local telephone lines for transmission to a receiver located at a suitable central location, so that the information can in turn be relayed to the appropriate agency (e.g. fire department, police department) or other desired recipient.
While all these systems are generally effective, there are certain problems, the most significant of which is the lack of flexibility of the units. For example, most existing communicators include "hard wiring" to meet the particular requirements of a given installation. This "customization" not only increases initial cost but also presents a problem if the protective circuits are to be changed or modified.
Typically again, a practical problem is encountered at the central receiving station because of the time involved in communication of a given alarm so that a limited number of local communicators can be connected to a single central receiver, thus further increasing not only initial cost but subsequent maintenance.
Furthermore, since the alarm reporting is dependent upon the integrity of the telephone line, if, for example, a burglar were to cut the telephone line prior to his entry, no information would thereafter be transmitted to the central location so that the entire security system would break down.